Coil and method of making same

ABSTRACT

A coil for transfer of information or energy is described. The coil includes an electrically conductive magnetically insulative first layer and a magnetically conductive second layer bonded to the first layer along the length of the first layer. The first and second layers are wound to form a plurality of substantially concentric loops. A width and a length of the second layer may be substantially co-extensive with a respective width and length of the first layer so as to expose opposing longitudinal edge surfaces of the first layer along the length of the first layer. At least one of the opposing longitudinal edge surfaces may include a regular pattern extending substantially along a same first direction and across substantially the entire coil. A method of making the coil is described.

BACKGROUND

Coils used in antennas are known. Inductive coupling between coils canbe used in wireless power systems. In this approach, a transmitter coilin one device transmits electric power across a short distance to areceiver coil in another device.

SUMMARY

In some aspects of the present description, an antenna for transfer ofinformation or energy is provided. The antenna includes an electricallyconductive magnetically insulative first layer having a width W, athickness T, and extending longitudinally along a length L of the firstlayer between first and second longitudinal ends of the first layer, anda magnetically conductive second layer bonded to the first layer alongthe length of the first layer. The first and second layers are wound toform a plurality of substantially concentric loops. A width and a lengthof the second layer are substantially co-extensive with the respectivewidth and length of the first layer so as to expose opposinglongitudinal edge surfaces of the first layer along the length of thefirst layer.

In some aspects of the present description, a coil including amultilayer film wound to form a plurality of substantially concentricloops is provided. The multilayer film includes a magneticallyconductive first layer and a plurality of alternating second and thirdlayers disposed on and bonded to the first layer. The second layers areelectrically conductive and magnetically insulative. The third layersare electrically and magnetically insulative. Widths and lengths of thefirst, second and third layers are substantially co-extensive with eachother so that no longitudinal edge surface of a second layer is coveredby either a third layer or the first layer.

In some aspects of the present description, a coil including a pluralityof substantially concentric loops is provided. Each loop includes anedge surface substantially perpendicular to an adjacent loop. The edgesurface includes a regular pattern extending along a first directionmaking an angle θ with a longitudinal direction of the loop. θ variesalong the longitudinal direction of the loop.

In some aspects of the present description, a coil including a pluralityof substantially concentric loops is provided. Each loop includes anedge surface substantially perpendicular to an adjacent loop. The edgesurface includes a regular pattern extending substantially laterallyacross the edge surface. The regular patterns of the edge surfaces of atleast a plurality of adjacent loops are substantially aligned with eachother.

In some aspects of the present description, a coil including a pluralityof substantially concentric loops is provided. Each loop includes aplurality of substantially concentric metal layers substantiallyconcentric with at least one soft magnetic layer, such that in a planview, the coil includes a regular pattern of substantially parallelgrooves extending across at least a plurality of adjacent loops in theplurality of substantially concentric loops.

In some aspects of the present description, a coil including a pluralityof substantially concentric loops is provided. Each loop includes aplurality of substantially concentric alternating metal and firstadhesive layers. A second adhesive layer is disposed between and bondingadjacent loops. The second adhesive layer is thicker than the firstadhesive layer.

In some aspects of the present description, a coil including a pluralityof substantially concentric loops is provided. Each loop includes ametal layer. In a plan view, the coil includes a regular patternextending substantially along a same first direction and acrosssubstantially the entire coil. The regular pattern has a first averagepitch in a first region of the coil and a different second average pitchin a different second region of the coil.

In some aspects of the present description, a coil including a pluralityof substantially concentric loops is provided. Each loop includes ametal layer. In a plan view, the coil includes a regular patternextending substantially along a same first direction and acrosssubstantially the entire coil. A Fourier transform of the regularpattern has a peak at a first spatial frequency in a first region of thecoil and a peak at a different second spatial frequency in a differentsecond region of the coil.

In some aspects of the present description, an antenna for transfer ofinformation or energy is provided. The antenna includes a plurality ofsubstantially concentric loops, each loop including a metal layer, suchthat in a plan view and in at least one first region of the antenna, theantenna includes a regular optical and topographical pattern along afirst direction, and a regular optical, but not topographical, patternalong an orthogonal second direction.

In some aspects of the present description, an antenna for transfer ofinformation or energy is provided. The antenna includes an electricallyconductive magnetically insulative first layer having opposing majorsurfaces and opposing edge surfaces connecting the opposing majorsurfaces and a magnetically conductive second layer disposed on andbonded to the first layer and substantially co-extensive in length andwidth of the first layer so as to not cover edge surfaces of the firstlayer. The first and second layers are wound to form a plurality ofsubstantially concentric loops.

In some aspects of the present description, a substantially planar coilfor transfer of information or energy is provided. The coil includes anelectrically conductive magnetically insulative first layer and amagnetically conductive second layer disposed on and bonded to the firstlayer and substantially co-extensive in length and width of the firstlayer so as to not cover edge surfaces of the first layer.

In some aspects of the present description, a coil including amultilayer film wound to form a plurality of substantially concentricloops is provided. The multilayer film incudes an electricallyconductive magnetically insulative first layer, and a magneticallyconductive second layer disposed on and bonded to the first layer, suchthat corresponding edge surfaces of the first and second layers aresubstantially co-planar.

In some aspects of the present description, a coil or antenna includinga plurality of loops is provided. Each loop includes at least oneelectrically conductive layer and at least one other layer. Each loopmay include a plurality of electrically conductive layers which mayalternate with a plurality of adhesive layers. The at least one otherlayer may include one or more magnetically conductive and/ormagnetically soft layers. In some aspects of the present description, amethod of making the coil or antenna is provided. The method includescutting or slicing through an assembly to provide a separated portion ofthe assembly that includes the coil or antenna.

In some aspects of the present description, an assembly including a rodand a multilayer film wound around a plurality of consecutive turnssubstantially concentric with the rod is provided. The multilayer filmincludes a plurality of alternating metal and first adhesive layers, anda magnetically conductive second layer disposed on and bonded to theplurality of alternating metal and first adhesive layers.

In some aspects of the present description, a method of making a coil isprovided. The method includes providing a rod; providing a multilayerfilm including an electrically conductive first layer and a magneticallyconductive second layer disposed on the first layer; winding themultilayer film around the rod to form an assembly including the rod anda plurality of loops of the multilayer film substantially concentricwith the rod; and cutting substantially laterally through the assemblyto form a separated portion of the assembly. The separated portion ofthe assembly includes the coil. The coil includes a plurality ofsubstantially concentric loops of a separated portion the multilayerfilm.

In some aspects of the present description, a method of making a coil isprovided. The method includes providing a rod; providing a multilayerfilm including a plurality of alternating electrically conductive andfirst adhesive layers and including a second adhesive layer including anoutermost major surface of the multilayer film; winding the multilayerfilm around the rod to form an assembly including the rod and aplurality of loops of the multilayer film substantially concentric withthe rod, where each loop is bonded to an adjacent loop through thesecond adhesive layer; and cutting substantially laterally through theassembly to form a separated portion of the assembly. The separatedportion of the assembly includes the coil. The coil includes a pluralityof substantially concentric loops of a separated portion the multilayerfilm.

In some aspects of the present description, a method of making aplurality of coils is provided. The method includes providing a rod;providing a multilayer film including an electrically conductive firstlayer and a second layer disposed on and bonded to the first layer;winding the multilayer film around the rod to form an assembly includingthe rod and a plurality of loops of the multilayer film substantiallyconcentric with the rod; and slicing substantially laterally through theassembly using a plurality of spaced apart cutting wires to form aplurality of separated portions of the assembly, where each separatedportion of the assembly includes a coil in the plurality of coils, andeach coil includes a plurality of substantially concentric loops of aseparated portion the multilayer film.

In some aspects of the present description, a method of making a coil isprovided. The method includes providing an assembly comprising a rod anda film wound around a plurality of consecutive turns substantiallyconcentric with the rod, the film comprising an electrically conductivefirst layer; and slicing substantially laterally through the assemblyusing at least one cutting wire to form a separated portion of theassembly including the coil, where the coil includes a plurality ofsubstantially concentric loops of a separated portion the film.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1B are a schematic top plan and side views of a coil,respectively;

FIG. 1C is a schematic cross-sectional view of a multilayer film of thecoil of FIGS. 1A-1B;

FIG. 1D is a schematic top plan view of an assembly including the coilof FIGS. 1A-1B;

FIG. 2 is a schematic top plan view of a coil;

FIGS. 3A-3B are schematic top plan views of a coil;

FIG. 3C is a schematic bottom plan view of the coil of FIGS. 3A-3B;

FIG. 4 is a schematic end view of a multilayer film;

FIGS. 5A-5B are schematic end and side views of a multilayer film,respectively;

FIG. 6 is a top view of an assembly including an antenna;

FIG. 7A is a laser intensity image of a portion of a coil;

FIG. 7B is a schematic top plan view of a portion of a coil;

FIGS. 8A-8B are a laser intensity image and a topographical map,respectively, of a first region of a coil;

FIG. 9 is a topographical map of a portion of the first region of thecoil of FIGS. 8A-8B;

FIG. 10 is a plot of the topography in the first region of the coil ofFIGS. 8A-8B along a first direction;

FIG. 11 is a plot of the topography in the first region of the coil ofFIGS. 8A-8B along an orthogonal second direction;

FIG. 12 is a plot of the magnitude of a two-dimensional Fouriertransform of the surface topography in the first region of the coil ofFIGS. 8A-8B;

FIG. 13 is a plot of the magnitude of Fourier transform of the surfacetopography along the first direction in the first region of the coil ofFIG. 12 ;

FIG. 14 is a plot of the magnitude Fourier transform of the surfacetopography along the second direction in the first region of the coil ofFIG. 12 ;

FIGS. 15A-15B are a laser intensity image and a topographical map,respectively, of a second region of the coil of FIGS. 8A-8B;

FIG. 16 is a topographical map of a portion of the second region of thecoil of FIGS. 15A-15B;

FIG. 17 is a plot of the topography in the second region of the coil ofFIGS. 15A-15B along the first direction;

FIG. 18 is a plot of the topography in the second region of the coil ofFIGS. 15A-15B along the second direction;

FIG. 19 is a plot of the magnitude of the Fourier transform of thesurface topography in the second region of the coil of FIGS. 15A-15B;

FIG. 20 is a plot of the magnitude Fourier transform of the surfacetopography in the second region of the coil of FIGS. 15A-15B along thefirst direction;

FIG. 21 is a plot of the magnitude Fourier transform of the surfacetopography in the second region of the coil of FIGS. 15A-15B along thesecond direction.

FIGS. 22A-22B are a laser intensity image and a topographical map,respectively, of a third region of the coil of FIGS. 8A-8B;

FIG. 23 is a plot of the topography in the third region of the coil ofFIGS. 22A-22B along the second direction;

FIG. 24 is a plot of the magnitude of the Fourier transform of thesurface topography in the third region of the coil of FIGS. 22A-22B;

FIG. 25 is a plot of the magnitude of the Fourier transform of thesurface topography in the third region of the coil of FIGS. 22A-22Balong the first direction;

FIG. 26 is a plot of the magnitude of the Fourier transform of thesurface topography in the third region of the coil of FIGS. 22A-22Balong the second direction;

FIGS. 27A-27B are a laser intensity image and a topographical map,respectively, in a fourth region of the coil of FIGS. 8A-8B;

FIG. 28 is a plot of the topography in the fourth region of the coil ofFIGS. 27A-27B along the second direction;

FIG. 29 is a plot of the magnitude of the Fourier transform of thesurface topography in the fourth region of the coil of FIGS. 27A-27B;

FIG. 30 is a plot of the Fourier transform of the surface topography inthe fourth region of the coil of FIGS. 27A-27B along the firstdirection;

FIG. 31 is a plot of the magnitude of the Fourier transform of thesurface topography in the fourth region of the coil of FIGS. 27A-27Balong the second direction;

FIG. 32 is a top plan view of a coil;

FIGS. 33A-33B are a laser intensity image and a topographical map,respectively, of a comparative coil in a first region;

FIG. 34 is a topographical map of a portion of the first region of thecoil of FIGS. 33A-33B;

FIGS. 35A-35B are plots of the topography in the first region of thecoil of FIGS. 33A-33B along the first direction at smaller and largercoordinate length scales, respectively;

FIG. 36 is a plot of the topography in the first region of the coil ofFIGS. 33A-33B along the second direction in the first region;

FIG. 37 is a plot of the magnitude of the Fourier transform of thesurface topography in the first region of the coil of FIGS. 33A-33B;

FIG. 38 is a plot of the magnitude of the Fourier transform of thesurface topography in the first region of the coil of FIGS. 33A-33Balong the first direction;

FIG. 39 is a plot of the magnitude of the Fourier transform of thesurface topography in the first region of the coil of FIGS. 33A-33Balong the second direction;

FIGS. 40A-40B are a laser intensity image and a topographical map,respectively, of the comparative coil of FIGS. 33A-33B in the secondregion;

FIG. 41 is a topographical map of a portion of the second region of thecoil of FIGS. 40A-40B;

FIG. 42 is a plot of the topography in the second region of the coil ofFIGS. 40A-40B along the first direction;

FIGS. 43A-43B are plots of the topography in the second region of thecoil of FIGS. 40A-40B along the second direction at smaller and largercoordinate length scales, respectively;

FIG. 44 is a plot of the magnitude of the Fourier transform of thesurface topography in the second region of the coil of FIGS. 40A-40B;

FIG. 45 is a plot of the Fourier transform of the surface topography inthe second region of the coil of FIGS. 40A-40B along the firstdirection;

FIG. 46 is a plot of the Fourier transform of the surface topography inthe second region of the coil of FIGS. 40A-40B along the seconddirection;

FIG. 47 is a top plan view of a coil;

FIGS. 48A-48B are a laser intensity image and a topographical map,respectively, of a comparative coil in a first region of the coil;

FIG. 48C is a topographical map of a portion of the first region of thecoil of FIGS. 48A-48B;

FIGS. 49A-49B are plots of topography in the first region of the coil ofFIGS. 48A-48B along the first direction at smaller and larger coordinatelength scales, respectively;

FIG. 50 is a plot of the topography in the first region of the coil ofFIGS. 48A-48B along the second direction;

FIG. 51 is a plot of the magnitude of the Fourier transform of thesurface topography in the first region of the coil of FIGS. 48A-48B;

FIG. 52 is a plot of the magnitude of the Fourier transform of thesurface topography in the first region of the coil of FIGS. 48A-48Balong the first direction;

FIG. 53 is a plot of the Fourier transform of the surface topography inthe first region of the coil of FIGS. 48A-48B along the seconddirection;

FIGS. 54A-54B are a laser intensity image and a topographical map,respectively, of a second region of the coil of FIGS. 48A-48B;

FIG. 55 is a topographical map of a portion of the second region of thecoil of FIGS. 54A-54B;

FIG. 56 is a plot of the topography in the second region of the coil ofFIGS. 54A-54B along the first direction;

FIGS. 57A-57B are plots of the topography in the second region of thecoil of FIGS. 54A-54B along the second direction at smaller and largercoordinate length scales, respectively;

FIG. 58 is a plot of the magnitude of the Fourier transform of thesurface topography in the second region of the coil of FIGS. 54A-54B;

FIG. 59 is a plot of the Fourier transform of the surface topography inthe second region of the coil of FIGS. 54A-54B along the firstdirection;

FIG. 60 is a plot of the Fourier transform of the surface topography inthe second region of the coil of FIGS. 54A-54B along the seconddirection;

FIG. 61 is a schematic illustration of a multilayer film having an endinserted into a slit in a rod;

FIG. 62 is a schematic illustration of a multilayer film being woundaround a rod;

FIG. 63 is a schematic perspective view of an assembly;

FIG. 64 is a schematic illustration of slicing an assembly to make oneor more coils;

FIG. 65 is a schematic side perspective view of a diamond wire; and

FIG. 66 is a schematic side view of a transceiver.

DETAILED DESCRIPTION

In the following description, reference is made to the accompanyingdrawings that form a part hereof and in which various embodiments areshown by way of illustration. The drawings are not necessarily to scale.It is to be understood that other embodiments are contemplated and maybe made without departing from the scope or spirit of the presentdescription. The following detailed description, therefore, is not to betaken in a limiting sense.

Coils described herein may be useful for transfer of information (e.g.,digital or analogue data) or energy (e.g., energy for wirelesscharging). Coils which incorporate layer(s) which are magneticallyconductive and/or magnetically soft along with electrically conductivelayer(s) have been found to be useful in applications where it isdesired to efficiently transfer information or energy. For example, thecoil can be useful in the wireless charging of batteries that powerelectronic devices, such as cellular telephones. The coils can serve toguide magnetic fields during wireless charging, to shield the batteryand/or other electronic device components from electromagnetic fields,to reduce eddy currents induced by magnetic fields, and/or to enhancetransfer efficiency and/or Q factor of wireless charging systems, forexample. The term antenna may be used to refer to a coil that isconfigured for transfer of information or energy, for example.

When higher permeability materials and lower permeability materials areused together (e.g., in a coil), magnetic field lines tend to be moreconcentrated in the higher permeability material and less concentratedin the low permeability material, so high permeability (e.g.,significantly higher than vacuum permeability) materials can bedescribed as magnetically conductive and low permeability (e.g.,comparable to vacuum permeability) materials can be described asmagnetically insulative.

A magnetically conductive material or layer is a material or layerhaving a relative permeability of at least 2, and a magneticallyinsulative material or layer is a material or layer having a relativepermeability of no more than 1.5. In some embodiments, a magneticallyconductive layer has a relative permeability of greater than 2, orgreater than 10, or greater than 100. In some embodiments, amagnetically insulative layer has a relative permeability of less than1.5, or less than 1.4, or less than 1.2, or less than 1.1, or less than1.05. In some embodiments, a magnetically insulative layer has arelative permeability in a range of 0.99 to 1.05, for example. In someembodiments, a coil includes a plurality of loops where each loopincludes a magnetically insulative layer and a magnetically conductivelayer. In some embodiments, a relative permeability of the magneticallyconductive layer is at least 10 times, or at least 100 times a relativepermeability of the magnetically insulative layer. The relativepermeability refers to the real part of the complex relativepermeability, unless indicated otherwise.

A substantially non-magnetic metal is a metal having a relativepermeability close to unity (e.g., in a range of 0.98 to 1.1, or 0.99 to1.05, or 0.99 to 1.01) and not having a stable magnetically orderedphase. A stable phase is a macroscopic phase that is thermodynamicallystable at 20° C. in the absence of an applied magnetic field, unlessindicated differently. Magnetically ordered phases includeferromagnetic, antiferromagnetic, and ferrimagnetic phases.

A soft magnetic material or layer is a material or layer having acoercivity of no more than 1000 A/m. Coercivity is a measure of themagnetic field strength needed to demagnetize a material. Soft magneticmaterials or magnetic materials having low coercivity can be describedas magnetic materials that are easily demagnetized. In some embodiments,a soft magnetic layer has a coercivity of less than 1000 A/m, or lessthan 100 A/m, or less than 50 A/m, or less than 20 A/m.

In some embodiments, a magnetically conductive layer is softmagnetically. Such a layer may have a relative permeability of greaterthan 2, or greater than 10, or greater than 100; and a coercivity ofless than 1000 A/m, or less than 100 A/m, or less than 50 A/m, or lessthan 20 A/m.

A magnetically conductive layer or a soft magnetic layer may beelectrically conductive (e.g., an electrical resistivity of no more than200 μΩcm) or electrically insulative (e.g., an electrical resistivity ofat least 100 Ωm). In some embodiments, an electrically insulative layer(e.g., a magnetically conductive electrically insulative layer or a softmagnetic layer that is electrically insulative) has as an electricalresistivity of greater than 100 Ωm, or greater than 200 Ωm, or greaterthan 500 Ωm, or greater than 1000 Ωm. In some embodiments, anelectrically conductive layer (e.g., a magnetically insulativeelectrically conducive layer, or a magnetically conductive electricallyconducive layer, or a soft magnetic layer that is electricallyconductive) has as an electrical resistivity of less than 200 μΩcm, orless than 100 μΩcm, or less than 50 μΩcm, or less than 20 μΩcm, or lessthan 10 μΩcm. In some embodiments, a magnetically conductive and/ormagnetically soft material is electrically conductive. An electricallyconductive layer can be formed as a continuous layer of such magneticmaterials. An electrically insulative layer can be formed by dispersingparticles of such magnetic materials in an electrically insulativebinder at concentrations where electrically continuous paths through thelayer do not form. At higher concentrations, the layer can becomeelectrically conductive. In some embodiments, a composite layer includesdifferent types of soft magnetic particles where some particles areelectrically conductive and other particles are electrically insulative.The resistivity can be adjusted by adjusting the volume fraction of theconductive particles. Electrical resistivity refers to the intrinsicelectrical resistivity, unless indicated differently.

Magnetic and electric properties (e.g., relative permeability,coercivity, electrical resistivity) refers to the respective propertyevaluated at low frequencies (e.g., about 1 kHz or less) or evaluatedstatically (direct current), unless indicated differently, anddetermined at 20° C., unless indicated differently.

Any suitable magnetic material can be used for a magnetically conductiveand/or soft magnetic layer. Crystalline alloys including any two or allthree of iron, cobalt, or nickel can be used. Additional elements canoptionally be added to modify properties such as magnetostriction,resistivity, permeability, saturation induction, coercivity, remanence,and/or corrosion, for example. Examples of such alloys include NiFe,NiFeMo, Fe Si, FeAlSi, and FeCo. Amorphous alloys may also be used. Forexample, amorphous alloys including cobalt and/or iron with metalloidssuch as silicon and boron may be used. Such alloys are known in the art.Nanocrystalline materials such as nanocrystalline alloys may also beused. For example, nanocrystalline alloys including iron, silicon and/orboron, and optional other elements added to control the nucleation andgrowth of nanocrystals on annealing may be used. Many of these alloysinclude iron, silicon, boron, niobium, and copper. Useful FeSiBNbCualloys include those available from VACUUMSCHMELZE GmbH & co. under thetradename VITROPERM and those available from Hitachi Metals, Ltd. underthe tradename FINEMET. Ferrites can also be used. Ferrites includeoxides of iron and at least one other metal. Examples of useful ferritesinclude soft cubic ferrite materials, such as MnZn-ferrites orNiZn-ferrites. Such materials are available from many suppliers, such asFerroxcube.

In some embodiments, a magnetically conductive and/or soft magneticlayer includes a metal such as an alloy, for example. In someembodiments, the alloy is an iron alloy. In some embodiments, the alloyincludes iron and at least one of silicon, aluminum, boron, niobium,copper, cobalt, nickel, or molybdenum. In some embodiments, the alloyincludes iron and at least one of silicon, boron, niobium, or copper. Insome embodiments, the alloy includes iron, silicon, and boron, and insome embodiments, the alloy further includes niobium and copper. In someembodiments, the alloy includes iron and at least one of silicon andaluminum. In some embodiments, the alloy includes iron, aluminum andsilicon. In some embodiments, the alloy includes nickel and iron. Insome embodiments, the alloy includes iron, cobalt and nickel. In someembodiments, the alloy includes nickel, iron and molybdenum. In someembodiments, the alloy includes iron and silicon. In some embodiments,the alloy includes nickel, iron and molybdenum. In some embodiments, thealloy is a crystalline alloy. In some embodiment, the crystalline alloyincludes at least two different metals selected from iron, cobalt andnickel. In some embodiments, the alloy is a nanocrystalline alloy. Insome embodiments, the nanocrystalline alloy includes iron, silicon,boron, niobium, and copper. In some embodiments, the alloy is anamorphous alloy. In some embodiments, an amorphous alloy includes atleast one of cobalt or iron, and at least one of silicon or boron. Insome embodiments, a magnetically conductive and/or soft magnetic layerincludes a ferrite, such as a manganese-zinc ferrite or a nickel-zincferrite.

In some embodiments, a continuous electrically conductive layer of theiron alloy is used as a magnetically conductive and/or soft magneticlayer. In some embodiments, a magnetically conductive layer or a softmagnetic layer includes particles (e.g., magnetically conductive filler)dispersed in a binder (e.g., at least one of a thermoset adhesive, anepoxy, or a mixture including an epoxy). The magnetically conductivefiller can be or include particles of any of the magnetic materialsdescribed above. In some embodiments, the particles are metallicparticles which may be or include an iron-silicon-boron-niobium-copperalloy, for example, or which may be or include an iron-aluminum-siliconalloy (e.g., sendust), for example. In some embodiments, the particlesare ferrite particles such as manganese-zinc ferrite particles ornickel-zinc ferrite particles. Other suitable materials for theparticles, or for a continuous magnetically conductive and/or softmagnetic layer, include permalloy, molybdenum permalloy, andsupermalloy. Combinations of different particles may also be used. Insome embodiments, the particles include metallic particles which includeat least one of an iron-silicon-boron-niobium-copper alloy or aniron-aluminum-silicon alloy. The particles can have any suitable shapeand size. In some embodiments, the particles are flakes. A flake mayhave a thickness small (e.g., smaller by a factor of at least 4, or atleast 8) compared to a largest lateral dimension of the flake and mayhave an irregular edge shape, for example.

Useful electrically conductive magnetically insulative materials includesubstantially non-magnetic metals such as non-ferrous metals andaustenitic stainless steels, for example. A non-ferrous metal is ametal, which may be an elemental metal or a metal alloy, which does notcontain iron in appreciable amounts (e.g., no iron, or only smallamounts (e.g., trace amounts) of iron that do not materially affect themagnetic properties of the metal). Useful non-ferrous metals includealuminum, copper, zinc, lead, silver and alloys thereof, for example. Insome embodiments, an electrically conductive magnetically insulativelayer used in an antenna or coil is or includes a metal which may be orinclude copper or a copper alloy, for example.

In some aspects of the present description, methods of efficientlymaking coil(s) or antenna(s) are described. In some embodiments, amethod of making a coil or antenna includes the step of winding a filmhaving at least one electrically conductive layer around a rod to forman assembly as described further elsewhere herein. The film may includeone or more metal layers, for example. Using multiple thinner metallayers allows winding the film around the rod to form loops or turnssubstantially concentric with the rod to be carried out more easily thanif a single metal layer having the same total thickness (e.g., toprovide substantially the same low-frequency resistance along thelength) were used, for example. In some cases, multiple thinner layersare advantageously used to provide increased surface area which reducesthe buildup of the effective electrical resistance of the coil due tothe decrease in skin depth at higher frequencies. In some embodiments, amethod of making coil(s) or antenna(s) include slicing through theassembly with one or more diamond wires to form section(s) of theassembly that include the coil(s) or antenna(s). This slicing, or othermethods, can generate a regular pattern (e.g., a regular pattern ofsubstantially parallel grooves) on one or both sides of the coil orantenna. Such regular patterns are described further elsewhere herein.

Substantially concentric objects (e.g., substantially concentric loopsin a coil) have a same or close center (e.g., centered to within 20%, orwithin 10%, or within 5% of a largest lateral dimension (e.g., diameterof outermost loop)). Substantially concentric loops can have asubstantially circular, elliptical, or rounded rectangular shape, forexample.

The multilayer film can include adjacent layers bonded to one anotherthrough an adhesive layer and adjacent loops of the coil or antenna canbe bonded to one another through an adhesive layer. Useful adhesives maybe one or more of thermoset adhesives, epoxies, acrylates, orpolyurethanes, for example.

The present application is related to U.S. Prov. Appl. No. 62/725,649,filed on Aug. 31, 2018 and titled “Coil and Method of Making Same”,which is hereby incorporated herein by reference in its entirety.

FIGS. 1A-1B are a schematic top and side views of a coil 100 accordingto some embodiments. The coil 100 may be, or may be used in, an antennafor transfer of information or energy. The coil or antenna 100 includesa first layer 10 having a width W, a thickness T, and extendinglongitudinally along a length of the first layer 10 between first 11 andsecond 12 longitudinal ends of the first layer 10. The antenna 100further includes a second layer 20 bonded to the first layer 10 alongthe length of the first layer 10. The first and second layers 10 and 20are wound to form a plurality of substantially concentric loops 110. Awidth W1 and a length of the second layer are substantially co-extensivewith the respective width W and length of the first layer so as toexpose opposing longitudinal edge surfaces 13 and 14 of the first layer10 along the length of the first layer 10. In some embodiments, thefirst layer 10 is an electrically conductive magnetically insulativelayer and the second layer 20 is a magnetically conductive layer. Thesecond layer 20 has opposing longitudinal edge surfaces 21 and 26 alongthe length of the second layer 20 and has first and second longitudinalends 27 and 28. Longitudinal edge surfaces of a layer extend in alongitudinal direction (e.g., longitudinal direction 123 depicted inFIG. 3A) of the layer while longitudinal ends of a layer are disposed atends of the layer opposite one another in the longitudinal direction.

If a first length or width of a first layer is substantiallyco-extensive with a first length or width of a second layer, therespective lengths or widths substantially overlap each other (e.g., thefirst length or width overlaps at least 80%, or at least 90%, or atleast 95% of the second length or width; and the first length or widthoverlaps at least 80%, or at least 90%, or at least 95% of the firstlength or width).

In some embodiments, the antenna or coil 100 further includes at leastone third layer 17 bonded to the first layer 10 along the length of thefirst layer 10. Each third layer 17 has a width and a lengthsubstantially co-extensive with the respective width and length of thefirst layer 10. The first layer 10, the second layer 20, and the atleast one third layer 17 are wound to form the plurality ofsubstantially concentric loops 110. Each third layer 17 has opposinglongitudinal edge surfaces 33 and 34 along the length of the secondlayer 20 and has first and second longitudinal ends 18 and 19.

In some embodiments, the coil 100 includes first adhesive layer(s) 30bonding the first layer 10 and the at least one third layer 17 andincludes a second adhesive layer 42 disposed between and bondingadjacent loops 110. In some embodiments, the second adhesive layer 42 isthicker (e.g., by at least a factor of 1.5 or 2) than the first adhesivelayer 30. The coil 100 further includes a third adhesive layer 40bonding the first layer 10 to second layer 20. In some embodiments, thethird adhesive layer 40 is thicker (e.g., by at least a factor of 1.5 or2) than the first adhesive layer 30. In some embodiments, the at onethird layer 117 includes at least one electrically conductivemagnetically insulative layer. In some embodiments, the at least onethird layer 117 includes at least one magnetically conductive layer.

In some cases, the first layer 10 and each third layer 17 are similar incomposition, shape or function, for example. In such cases, or in othercases, the first layer 10 together with the one or more third layers 17may be described as a plurality of first layers. It will be understoodthat alternate nomenclatures can be used for the various layers. Forexample, the layer 20 may be described as a first layer and the layer 10together with the one or more third layers 17 may be described as aplurality of second layers.

The thicknesses and widths of the various layers may be selected to beany suitable values. In some embodiments, thinner first layers 10 and/orthird layers 17 are selected when it is desired for the coil or antennato operate at higher frequencies, and thicker first layers 10 and/orthird layers 17 are selected when it is desired for the coil or antennato operate at lower frequencies. At higher frequencies, current canbecome partially confined to a skin layer at the surface of theconductor and this tends to increase the effective electrical resistanceof the coil. Using multiple first layers 10 and/or third layers 17distributes the current over more surfaces and this can reduce theeffects of the reduced skin depth on the effective electrical resistanceof the coil. In some embodiments, each of the first layers 10 and/orthird layers 17 have a thickness of at least 5 microns, or at least 10microns, or at least 20 microns, or at least 40 microns. In someembodiments, each of the first layers 10 and/or third layers 17 have athickness of no more than 2000 microns, or no more than 1000 microns, orno more than 500 microns, or no more than 250 microns. For example, insome embodiments, 1000 microns≥T≥10 microns. The width (e.g., W or W1)of a layer may be less than, comparable to (e.g., equal to within 20%,or with 10%), or greater than the thickness of the layer. In someembodiments, a ratio of the width to a thickness of the first layer 10is at least 0.1, or at least 1, or at least 5 (i.e., in someembodiments, W/T≥0.1, or W/T≥1, or W/T≥5). For example, in someembodiments, 1000≥W/T≥0.1. The second layer 20 has a thickness T1. Insome embodiments, a ratio of the width to a thickness of the secondlayer 20 is at least 0.1, or at least 1, or at least 5, or at least 10(i.e., in some embodiments, W1/T1≥0.1, or W1/T1≥1, or W1/T1≥5, orW1/T1≥10). For example, in some embodiments, 1000≥W1/T1≥0.1. In someembodiments, the thickness T of the first layer 10 is greater than thethickness T1 of the second layer 20. In other embodiments, the thicknessT of the first layer 10 is less than the thickness T1 of the secondlayer 20. In some embodiments, the thicknesses T and T1 of the first andsecond layers 10 and 20 are about equal. The length of any of the layerslayer may be substantially longer than the width or thickness of thelayer (e.g., the length may be at least 5 times or at least 10 times oneor both of the width and the thickness).

In some embodiments, the antenna or coil 100 can be described asincluding a multilayer film 202 wound to form the plurality ofsubstantially concentric loops 110 where the multilayer film 202includes a first layer 20 and a plurality of second layers (10 and 17)disposed on and bonded to the first layer 20. The first layer 10 and theat least one third layer 17 may be disposed on a same side as the secondlayer 20, or one or more of the first layer 10 and the at least onethird layer 17 may be disposed on one same side of the second layer 20and the remaining layers of the first layer 10 and the at least onethird layer 17 may be disposed on the opposite side of the second layer20.

In some embodiments, the multilayer film 202 includes a first layer(e.g., layer 20), and a plurality of alternating second (e.g., layers 10and 17) and third (e.g., layer 30) layers disposed on and bonded to thefirst layer. In some embodiments, the first layer is a magneticallyconductive layer, the second layers are electrically conducivemagnetically insulative layers, and the third layers are electricallyand magnetically insulative. The first layer may have a relativepermeability in any of the ranges described elsewhere herein formagnetically conductive layers. The first layer may be electricallyconductive or electrically insulative. The second and/or third layersmay have a relative permeability in any of the ranges describedelsewhere herein for magnetically insulative layers. Each third layermay be an adhesive (e.g., a thermoset adhesive and/or an epoxy). In someembodiments, widths and lengths of the first, second and third layersare substantially co-extensive with each other so that no longitudinaledge surface (e.g., edge surfaces 13 and 14) of a second layer iscovered by either a third layer or the first layer.

The antenna or coil 100 includes opposing major surfaces 76 and 77. Oneor both of the major surfaces 76 and 77 may include a regular pattern(e.g., regular pattern of substantially parallel grooves) as describedfurther elsewhere herein. For example, in some embodiments, the regularpattern may be described in any one or more of the following ways. Theregular pattern may extend substantially along a same first directionand across substantially the entire coil. The regular pattern may extendalong a first direction making an angle θ with a longitudinal directionof the loop where θ varies along the longitudinal direction of the loop.The regular patterns of the edge surfaces of at least a plurality ofadjacent loops of the separated portion of the multilayer film may besubstantially aligned with each other. The regular pattern may include apattern of substantially parallel grooves extending across at least aplurality of adjacent loops of the separated portion of the multilayerfilm. The regular pattern may have a first average pitch in a firstregion of the coil and a different second average pitch in a differentsecond region of the coil. A Fourier transform of the regular patternmay have a peak at a first spatial frequency in a first region of thecoil and a peak at a different second spatial frequency in a differentsecond region of the coil. The coil may include, in at least one firstregion of the coil, a regular optical and topographical pattern along afirst direction, and a regular optical, but not topographical, patternalong an orthogonal second direction.

FIG. 1C is a schematic cross-sectional view of the multilayer film 202in a cross-section perpendicular to a longitudinal direction of theloops 110. The multilayer film 202 has a substantially rectangularcross-section. For example, the cross-section may be nominallyrectangular, or may be rectangular except for rounded corners havingradius of curvature large compared to the film thickness (e.g., at least5 times, or at least 10 times, or at least 20 times) and/or except forhaving opposite sides that deviate from parallel by no more than 20degrees, or no more than 10 degrees, or no more than 5 degrees. Therectangle can be longer or shorter or in the x-direction than in they-direction depending on the widths and thicknesses of the variouslayers. Substantially rectangular cross-sections also includesubstantially square cross-sections since square can be considered to bea special case of a rectangle. In some embodiments, for each loop in theplurality of substantially concentric loops 110, the multilayer film 202has a substantially rectangular cross-section in a plane perpendicularto a longitudinal direction of the loop. In some embodiments, each loopin the plurality of concentric loops 110 has a substantially rectangularcross-section in a plane perpendicular to the longitudinal direction ofthe loop.

FIG. 1D is a schematic top view of an assembly 101 including the coil100 and a rod 37. As described further elsewhere herein, the assembly101 can be made by wrapping a multilayer film around a rod and cutting(e.g., slicing with a wire saw) the resulting assembly to provide adesired width of a portion of the assembly separated by the cutting. Therod 37 may be a sliced segment of the initial rod used in forming theassembly 101.

The first layer 10 and the optional at least one third layer 17 may eachbe one or more of an electrically conductive magnetically insulativelayer, a metal layer, a non-ferrous metal layer, or a substantiallynon-magnetic metal layer and may have a conductivity and/or relativepermeability in any of the corresponding ranges described elsewhereherein and may be made of corresponding materials described elsewhereherein (e.g., copper or copper alloy). The second layer 20 may be one ormore of a magnetically conductive layer or a soft magnetic layer and mayhave a relative permeability and/or a coercivity in any of thecorresponding ranges described elsewhere herein and may be made ofcorresponding materials described elsewhere herein (e.g., particles ofan iron-silicon-boron-niobium-copper alloy in a binder). In someembodiments, each loop includes at least one metal layer (e.g., layer10) having a relative permeability less than 1.1 and at least one layer(e.g., layer 20) having a relative permeability of at least 10. In someembodiments, each loop 110 includes at least one substantiallynon-magnetic metal layer (e.g., layer 10) and at least one soft magneticlayer (e.g., layer 20). In some embodiments, each loop 110 includes atleast one electrically conductive magnetically insulative layer (e.g.,layer 10) and at least one magnetically conductive layer (e.g., layer20). In some embodiments, each loop 110 includes at least one firstlayer (e.g., layer 10 and/or 17) having an electrical resistivity ofless than 100 μΩcm and a relative permeability of less than 1.4 and atleast one second layer (e.g., layer 20) having a relative permeabilityof greater than 2 and a coercivity of less than 1000 A/m. In someembodiments, each loop includes at least one first layer (e.g., layer 10and/or 17) having an electrical resistivity of less than 100 μΩcm and arelative permeability of less than 1.1 and at least one second layer(e.g., layer 20) having a relative permeability of greater than 10 and acoercivity of less than 100 A/m.

In some embodiments, a coil or antenna 100 for transfer of informationor energy includes an electrically conductive magnetically insulativefirst layer 10 includes opposing major surfaces 15 and 16 and opposingedge surfaces 13 and 14 connecting the opposing major surfaces 15 and16; and a magnetically conductive second layer 20 disposed on and bondedto the first layer 10 and substantially co-extensive in length and widthof the first layer 10 so as to not cover edge surfaces 13 and 14 of thefirst layer, where the first and second layers 10 and 20 are wound toform a plurality of substantially concentric loops 110.

In some embodiments, the coil 100 is substantially planar. For example,the coil 100 may be disposed primarily in a plane parallel to the x-yplane of FIGS. 1A-1D referring to the illustrated x-y-z coordinatesystem and any radius of curvature of a cross-section of the coil in aplane perpendicular to plane of the coil is large (e.g., at least 5times, or at least 10 times, or at least 20 times) compared to adiameter or largest lateral dimension of the coil.

In some embodiments, a substantially planar coil 100 for transfer ofinformation or energy includes an electrically conductive magneticallyinsulative first layer 10, and a magnetically conductive second layer 20disposed on and bonded to the first layer 10 and substantiallyco-extensive in length and width of the first layer so as to not coveredge surfaces 13 and 14 of the first layer 10.

In some embodiments of the antenna or coil 100, corresponding edgesurfaces (13, 21 and 14, 22) of the first and second layers 10 and 20are substantially co-planar (see. e.g., planes S1 and S2 depicted inFIGS. 4 and 5A). The methods described elsewhere herein can, in someembodiments, ensure that the second layer 20 is substantiallyco-extensive in length and width of the first layer so as to not coveredge surfaces 13 and 14 of the first layer 10 and can, in someembodiments, form corresponding edge surfaces of the first and secondlayers 10 and 20 that are substantially co-planar.

The coil 100 is wound into loops with the second layer 20 outside thefirst layer 10. The coil can alternatively be wound into loops with thefirst layer 10 outside the second layer 20. FIG. 2 is a schematic topview of an antenna or coil 200 wound with the first layer 10 outside thesecond layer 20. In the illustrated embodiment, the coil 200 includes atleast one third layer 17 with the first layer 10 disposed between thesecond layer 20 and the at least one third layer 17.

FIGS. 3A-3B are schematic top views of an antenna or coil 300 where atleast one of the opposing longitudinal edge surfaces of the first layer10 includes a regular pattern 120. FIG. 3C is a schematic bottom view ofthe antenna or coil 300 according to some embodiments. The regularpattern 120 may be a regular pattern of grooves, for example. In someembodiments, the longitudinal edge surface 13 includes a first regularpattern (e.g., appearing as regular pattern 120 in top plan view) andthe longitudinal edge surface 14 includes a second regular pattern(e.g., appearing as regular pattern 120 b in bottom plan view). In otherembodiments, the regular pattern is present in only one or the other ofthe top and bottom plan views. The coil 100 and/or 200 may include theregular pattern(s) described for coil 300, for example.

In some embodiments, each loop 110 a in the plurality of substantiallyconcentric loops 110 has an edge surface 111 substantially perpendicular(e.g., within 20 degrees, or 10 degrees, or 5 degrees to perpendicular)to an adjacent loop 110 b and includes a regular pattern 120. In someembodiments, the regular pattern 120 extends along a first direction 122making an angle θ with a longitudinal direction 123 of the loop 110where θ varies along the longitudinal direction 123 of the loop 110. Insome embodiments, the regular pattern 120 extends substantiallylaterally across the edge surface 111 (e.g., within 20 degrees, orwithin 10 degrees, or within 5 degrees, or within 3 degrees of a planeof the major surface of the coil including the edge surface 111 (e.g.,parallel to the x-y plane)). In some embodiments, the regular pattern120 extends substantially laterally across the edge surface 111substantially along a same first direction 122. In some embodiments, theregular patterns 120 of the edge surfaces 111 of at least a plurality ofadjacent loops 110 are substantially aligned with each other. In someembodiments, each loop includes a second edge surface 111 b (see, e.g.,FIG. 3C) opposite the edge surface 111 (first edge surface), where thesecond edge surface 111 b includes a second regular pattern 120 b whichmay also extend along the first direction 122 and which may also extendsubstantially laterally across the second edge surface 111 b.

The second regular pattern 120 b may have any of the attributesdescribed further elsewhere herein for the regular pattern 120. Forexample, the second regular pattern 120 b may be a regular pattern ofsubstantially parallel grooves extending across at least a plurality ofadjacent loops in the plurality of substantially concentric loops.

In some embodiments, the substantially concentric loops refer to loopsof a multilayer film, for example. Each loop 110 may include loops ofadjacent layers 10 and 17 and the edge surface 111 may be an edgesurface of the combined adjacent layers 10 and 17. In some embodiments,the substantially concentric loops refer to loops of individual layersin a multilayer film, for example. For example, the first layer 10 iswound into substantially concentric loops. In such cases, the edgesurface 111 may be an edge surface (e.g., edge surface 13) of a firstlayer 10, for example.

In some embodiments, each loop 110 includes at least one layer (e.g.,layer 20) that is a soft magnetic layer and/or a magnetically insulativelayer and at least one layer (e.g., layer 10 and/or 17) that is anelectrically conductive layer such as a metal layer. In someembodiments, the optional at least one third layer 17 is omitted. Insome embodiments, each loop includes a plurality of electricallyconductive or metal layers (e.g., layers 10 and 17). In someembodiments, each loop includes two or more soft magnetic and/ormagnetically insulative layers.

In some embodiments, the coil 300 includes a plurality of substantiallyconcentric loops 110 where each loop includes a plurality ofsubstantially concentric metal layers (10 and 17) substantiallyconcentric with at least one soft magnetic layer 20, such that in a planview (e.g., the top plan view of FIG. 3A or 3B and/or the bottom planview of FIG. 3C), the coil 300 includes a regular pattern 120 ofsubstantially parallel grooves 121 extending across at least a pluralityof adjacent loops in the plurality of substantially concentric loops110. In some embodiments, in the top plan view, the coil includes theregular pattern 120 (first regular pattern) and in a bottom plan view,the coil includes a regular pattern 120 b (second regular pattern). Insome embodiments, each of the first and second regular patterns includea pattern of substantially parallel grooves. In some embodiments, thefirst and second regular patterns extend in substantially same firstdirection 122.

In some embodiments, the at least one soft magnetic layer of each loopis disposed between the plurality of substantially concentric metallayers of the loop and the plurality of substantially concentric metallayers of an adjacent loop. In some embodiments, a first adhesive layer30 is disposed between and bonds adjacent metal layers in the pluralityof substantially concentric metal layers, and a second adhesive layer 42is disposed between and bonds adjacent loops. In some embodiments, thesecond adhesive layer 42 is thicker than the first adhesive layer 30.

In some embodiments, the plurality of substantially concentric metallayers in each loop are electrically connected to each other. Forexample, the metal layers in each loop may be welded together at one orboth ends of the loop or may be electrically connected to one another atone or both ends of the loop when the coil is connected to electricalcable(s) by soldering, for example. A weld 15 is schematicallyillustrated in FIG. 3B. The opposite ends of the layers 10 and 17 mayalso optionally be welded or soldered to provide an electricalconnection between the layers

In some embodiments, the antenna or coil 300 includes a plurality ofsubstantially concentric loops 110, where each loop includes a metallayer (e.g., layer 10). Each loop may further include at least one softmagnetic layer and/or may include a plurality of alternating metal andfirst adhesive layers as described further elsewhere herein. In someembodiments, in a plan view (e.g., the top plan view of FIG. 3A), thecoil 300 includes a regular pattern 120 extending substantially along asame first direction 122 (e.g. extending along the first direction 122to within 20 degrees, or within 10 degrees, or within 5 degrees of thefirst direction 122) and across substantially the entire coil 300 (e.g.,across at least 80%, or at least 90%, or at least 95% of an area of thecoil). The regular pattern 120 can be described in terms of an averagepitch in various regions and/or in terms of a Fourier transform of theregular pattern in the various regions. In some embodiments, the regularpattern has a first average pitch P1 in a first region 125 of the coiland a different second average pitch P2 in a different second region 130of the coil. In some embodiments, a difference between the first andsecond average pitches is greater than about 10 microns, or greater thanabout 15 microns, or greater than about 20 microns, or greater thanabout 30 microns, or greater than about 40 microns, or greater thanabout 50 microns. For example, the first average pitch P1 may be in arange of about 60 microns to about 100 microns, and the second averagepitch P2 may be in a range of about 120 microns to about 200 microns. Insome embodiments, one or both of the first and second average pitchesare in a range from 5 microns, or 10 microns, or 20 microns, or 40microns to 2000 microns, or 1000 microns, or 500 microns, or 250microns.

In some embodiments, a Fourier transform of the regular pattern has apeak at a first spatial frequency (see, e.g., F1 depicted in FIG. 14 )in a first region 125 of the coil and a peak at a different secondspatial frequency (see, e.g., F2 depicted in FIG. 21 ) in a differentsecond region 130 of the coil. The peaks in the Fourier transforms maycorrespond to average pitches in the regular pattern (e.g., F1 may beabout 1/P1 and F2 may be about 1/P2). In some embodiments, one or bothof the first and second spatial frequencies are in a range from 1/(2000microns), or 1/(1000 microns), or 1/(500 microns), or 1/(250 microns) to1/(5 microns), or 1/(10 microns), or 1/(20 microns), or 1/(40 microns).In some embodiments, a difference between the first and second spatialfrequencies is greater than about 0.001 inverse microns, or greater thanabout 0.002 inverse microns, or greater than about 0.004 inversemicrons, or greater than about 0.01 inverse microns, or greater thanabout 0.02 inverse microns, or greater than about 0.05 inverse microns,or greater than about 0.1 inverse microns.

Third and fourth regions 131 and 139 are also illustrated in FIG. 3B.The pitch and Fourier transform can be evaluated in each of theseregions as described further elsewhere herein.

In some embodiments, coils or antennas (e.g., 100, 200, or 300) of thepresent description can be described as including a multilayer filmwound to form a plurality of substantially concentric loops (e.g., loops110).

FIG. 4 is a schematic end view of an embodiment of a multilayer film 402including a first layer 10 and a second layer 20. First layer 10 may bean electrically conductive magnetically insulative layer and secondlayer 20 may be a magnetically conducive layer and/or a soft magneticlayer. In some embodiments, the first layer 10 and the second layer 20are bonded to one another through an adhesive 40. In some embodiments, amultilayer film includes two multilayer films 402 with adhesive 42 ofone the films bonded to the first layer 10 of the other films. In suchembodiments, the multilayer film includes two first layers 10 and twosecond layers 20. In some embodiments, an antenna or coil includes themultilayer film 402 wound into a plurality of loops. In someembodiments, adhesive 42 bonds adjacent loops to one another.

In some embodiments, the multilayer film 402 includes an electricallyconductive magnetically insulative first layer 10, and a magneticallyconductive second layer 20 disposed on and bonded to the first layer 10,such that corresponding edge surfaces of the first and second layers 10and 20 are substantially co-planar (e.g., co-planar to within deviationsfrom a common plane of less than 0.3, or less than 0.2, or less than0.1, or less than 0.05 times the thickness of the multilayer film). Inthe illustrated embodiments, the edge surface 13 of the first layer 10and the edge surface 21 of the second layer 20 are corresponding edgesurfaces in the plane S1, and the edge surface 14 of the first layer 10and the edge surface 24 of the second layer 20 are corresponding edgesurfaces in the plane S2.

In some embodiments, a multilayer film includes additional first layers10 and/or additional second layers 20. FIG. 5A is a schematic end viewof the multilayer film 502 including a first layer 20 and a plurality ofalternating second and third layers 10 and 30. FIG. 5B is a schematicside view of the multilayer film 502. In some embodiments, themultilayer film 502 includes a magnetically conductive first layer 20;and a plurality of alternating second 10 and third 30 layers disposed onand bonded to the first layer 20, where the second layers 10 areelectrically conductive and magnetically insulative, and the thirdlayers 30 are electrically and magnetically insulative. In someembodiments, widths (W1, W, W2) and lengths (L1, L, L2) of the first,second and third layers 20, 10, and 30 are substantially co-extensivewith each other so that no longitudinal edge surface (13, 14) of asecond layer 10 is covered by either a third layer 30 or the first layer20. In some embodiments, a ratio of the width to a thickness of thefirst layer 20 is at least 0.1, or at least 1, or at least 5.

In some embodiments, a coil includes a multilayer film (e.g., 202, or402 or 502) wound to form a plurality of substantially concentric loops(e.g., loops 110). In some embodiments, the multilayer film includes aplurality of alternating electrically conductive 10 and first adhesive30 layers and includes a second adhesive layer 42 including an outermostmajor surface 44 of the multilayer film. The second adhesive layer 42can optionally be disposed at the opposite outermost major surface fromthat illustrated in FIGS. 4-5B. In some embodiments, as describedfurther elsewhere herein, a method of making a coil includes winding themultilayer film around the rod to form an assembly including the rod anda plurality of loops of the multilayer film substantially concentricwith the rod where each loop is bonded to an adjacent loop through thesecond adhesive layer 42.

A film may have two dimensions much larger than a third dimension. Afilm strip may be cut out from the film such that the strip has onedimension much larger than the other two dimensions. A multilayer filmused in a coil or antenna of the present description may be a film stripor a portion of a film strip.

FIG. 6 is a top view of an assembly 601 including a coil 600 and a rodor rod section 637. The coil 600 includes a plurality of substantiallyconcentric loops 110. FIG. 7A is a laser intensity image of a portion ofa coil corresponding to coil 600 obtained using a Keyence VHX-5000digital microscope fitted with a Z20 lens at 150× magnification. FIG. 7Bis a schematic top plan view of a portion of a coil which may correspondto coil 600. The coil of FIG. 7B is considered to have a curvature largecompared to the size of the illustrated portion so that the curvature isnot shown in the schematic illustration of FIG. 7B.

In some embodiments, the coil includes a plurality of substantiallyconcentric loops where each loop is a loop of a multilayer film (e.g.,loops 110 depicted in FIG. 7B include a plurality of layers 10 and 30).In some embodiments, the coil includes a plurality of substantiallyconcentric loops where each loop is a loop of a first layer (e.g., loops10 a and 10 b depicted in FIG. 7A or 7B are each loops of a single layer10). In some embodiments, a coil 600 includes a plurality ofsubstantially concentric loops 110, where each loop includes a pluralityof substantially concentric alternating metal 10 and first adhesivelayers 30 (e.g., each of the loops 110 a and 110 b depicted in FIG. 7Aor 7B each include alternating layers 10 and 30). In some embodiments,each metal layer includes a non-ferrous metal, and/or is magneticallyinsulative, and/or is substantially non-magnetic.

A second adhesive layer 41 is disposed between and bonds adjacent loops110. In some embodiments, the second adhesive layer 41 is thicker thanthe first adhesive layer 30. In some embodiments, the second adhesivelayer 41 is thicker than the first adhesive layer by at least a factorof two, of by at least a factor of four. In some embodiments, the secondadhesive layer 41 includes a magnetically conductive filler dispersed ina binder.

In some embodiments, the second adhesive layer 41 includes opposingfirst and second adhesive portions 40 and 42 on opposite major surfacesof a composite portion 20. The composite portion 20 includes particles43, which may be magnetically conductive filler particles, dispersed ina binder (e.g., epoxy). In some embodiments, each of the adhesiveportions 40 and 42 and the composite portions 20 include a common typeof adhesive material. For example, in some embodiments, each of theadhesive portions 40 and 42 and the composite portion 20 includes epoxy.In some embodiments, the composite portion 20 includes magneticallyconductive filler particles dispersed throughout the composite portion20 in order to increase the relative permeability of the compositeportion 20, for example. The particles 43 may be metal particles whichmay include an iron-silicon-boron-niobium-copper alloy, for example, andwhich may have any suitable shape (e.g., at least one of flakes, plates,spheres, ellipsoids, irregularly shaped particles).

In some embodiments, an antenna or coil includes a plurality ofsubstantially concentric loops 110, where each loop includes a pluralityof substantially concentric alternating metal 10 and first adhesivelayers 30, and where a second adhesive layer 41 is disposed between andbonds adjacent loops. In some embodiments, the second adhesive layerthicker than the first adhesive layer (e.g., by at least a factor of 2or 4). In some embodiments, each of the first and second adhesiveportions 40 and 42 is thicker than each first adhesive layer 30. In someembodiments, the composite portion 20 is thicker than each of the firstand second adhesive portions 40 and 42. In some embodiments, the firstand second adhesive portions 40 and 42 have a substantially (e.g., towithin 20%, or to within 10%, or to within 5%) same thickness.

In some embodiments, the antenna or coil includes a multilayer filmwound to form a plurality of substantially concentric loops, where themultilayer film includes a magnetically conductive first layer 20 and aplurality of alternating second 10 and third 30 layers. The first layer20 is bonded to the plurality of alternating second 10 and third 30layers through and adhesive layer 40. Adjacent loops are bonded togetherthrough adhesive layer 42. In some embodiments, the adhesive layer 42 isthicker than each layer 30. In some embodiments, the adhesive layer 42is thicker than each layer 30 by at least a factor of 1.5, or by atleast a factor of 2.

FIGS. 8A-8B are a laser intensity image and a topographical map,respectively, of a coil or antenna 800 in a first region (e.g.,corresponding to first region 125 depicted in FIG. 3B) of the antenna800 in a top plan view (e.g., in the x-y plane referring to the x-y-zcoordinate system depicted in FIG. 8 ) obtained using a Keyence VK-X200confocal microscope with a 20x objective. In some embodiments, theantenna 800 is for transfer of information or energy and includes aplurality of substantially concentric loops 110 where each loop includesa metal layer 10. In some embodiments, each loop 110 includes aplurality of metal layers 10 (e.g., four metal layers 10 in theillustrated embodiment). Coil or antenna 800 was made from a multilayerfilm including 4 copper layers bonded together with 10 micron thickepoxy adhesive layers 30, and an adhesive layer 41 which included acomposite layer (e.g., corresponding to layer 20 depicted in FIG. 7B)having a thickness of about 60 micrometers bonded to the copper layerswith a 20 micron thick epoxy adhesive layer (e.g., corresponding tolayer 40 depicted in FIG. 7B) and having a 20 micron thick epoxyadhesive layer (e.g., corresponding to layer 42 depicted in FIG. 7B) forbonding adjacent loops of the multilayer film together. The copperlayers had a thickness of about 105 microns. The composite layerincluded flakes of magnetic metal (sendust) dispersed in epoxy. The coilor antenna 800 was made by winding the multilayer film around a rod toform a plurality of substantially concentric loops and slicing the coilor antenna 800 from the resulting assembly using a diamond wire saw asdescribed further elsewhere herein.

FIG. 9 is a topographical map of a portion of the first region obtainedusing the Keyence VK-X200 confocal microscope. FIG. 10 is a plot of thetopography (height of surface relative to a reference plane) along thex-direction and FIG. 11 is a plot of the topography (height) along they-direction in the first region. The plots in FIGS. 10-11 were extractedfrom the topological map obtained using the Keyence VK-X200 confocalmicroscope. It can be seen in FIGS. 8A-9 that an optical pattern ispresent in both the x- and y-directions. It can be seen in FIG. 10 thatthere is substantially no topographical pattern along the y-directionacross the plurality of metal layers. It can be seen in FIG. 11 thatthere is a substantial topographical pattern along the y-directionacross the plurality of metal layers. The topological pattern in thefirst region had an average pitch P1 in the y-direction of about 89microns (determined by approximating the average pitch as the inverse ofthe corresponding Fourier transform peak frequency). In someembodiments, in a plan view (e.g., in the x-y plane) and in at least onefirst region 125 of the antenna or coil, the antenna or coil includes aregular optical and topographical pattern 120 along a first direction(y-direction), and a regular optical, but not topographical, patternalong an orthogonal second direction (x-direction). In some embodiments,in a top plan view and in at least one first region 125 of the antennaor coil, the antenna or coil includes a first regular optical andtopographical pattern 120 along a first direction (y-direction), and afirst regular optical, but not topographical, pattern along anorthogonal second direction (x-direction); and in a bottom plan view andin at least one first region 125 of the antenna or coil, the antenna orcoil includes a second regular optical and topographical pattern 120 b(schematically depicted in FIG. 3C) along the first direction, and asecond regular optical, but not topographical, pattern along anorthogonal second direction.

In some embodiments, the regular optical and topographical pattern 120and/or 120 b includes a regular pattern of substantially parallelgrooves extending along the second direction and spaced apart along thefirst direction. In some embodiments, the regular pattern ofsubstantially parallel grooves extends across substantially the entireantenna or coil, and the regular pattern of substantially parallelgrooves has a first average pitch in a first region of the antenna orcoil and has a different second average pitch in a different secondregion of the antenna or coil. In some embodiments, the regular patternof substantially parallel grooves extends across substantially theentire antenna and a Fourier transform of the regular pattern ofsubstantially parallel grooves has a peak at a first spatial frequencyin a first region of the antenna and a peak at a different secondspatial frequency in a different second region of the antenna.

FIG. 12 is a plot of the magnitude of a two-dimensional Fouriertransform of the surface topography in the first region. FIG. 13 is aplot of the magnitude of Fourier transform along the x-direction andFIG. 14 is a plot of the magnitude Fourier transform along they-direction in the first region. The Fourier transform along they-direction has a peak K1 at a spatial frequency F1. The peak K1 isindicative of the periodic pattern shown in FIG. 11 . The peak K1 issubstantially spaced apart from any neighboring peak. The Fouriertransform along the x-direction shown in FIG. 13 does not have a peak ata non-zero spatial frequency that is substantially spaced apart from anyneighboring peak. This indicates a lack of a topological pattern alongthe x-direction.

FIGS. 15A-15B are a laser intensity image and a topographical map,respectively, of the coil or antenna 800 in a second region (e.g.,corresponding to second region 130 depicted in FIG. 3B) of the coil orantenna 800 in a top plan view obtained using the Keyence VK-X200confocal microscope. FIG. 16 is a topographical map of a portion of thesecond region. FIG. 17 is a plot of the height along the x-direction andFIG. 18 is a plot of the height along the y-direction in the secondregion. The topological pattern in the second region had an averagepitch P2 in the y-direction of about 152 microns.

FIG. 19 is a plot of the magnitude of the Fourier transform of thesurface topography in the second region. FIG. 20 is a plot of themagnitude Fourier transform along the x-direction and FIG. 21 is a plotof the magnitude Fourier transform along the y-direction in the secondregion. The Fourier transform along the y-direction has a peak K2 at aspatial frequency F2. The peak K2 is indicative of the periodic patternshown in FIG. 18 . The peak K2 is substantially spaced apart from anyneighboring peak having a similar magnitude. The Fourier transform alongthe x-direction shown in FIG. 20 does not have any such peaks; thisindicates a substantial absence of a topological pattern along thex-direction.

FIGS. 22A-22B are a laser intensity image and a topographical map,respectively, of the coil or antenna 800 in a third region (e.g.,corresponding to third region 131 depicted in FIG. 3B) of the coil orantenna 800 in a top plan view obtained using the Keyence VK-X200confocal microscope. FIG. 23 is a plot of the height along they-direction. A periodic structure having an average pitch in they-direction of about 97.1 microns is visible. FIG. 24 is a plot of themagnitude of the Fourier transform of the surface topography in thethird region. FIG. 25 is a plot of the magnitude of the Fouriertransform along the x-direction and FIG. 26 is a plot of the magnitudeof the Fourier transform along the y-direction in the third region. Thepair of large peaks proximal to the zero-frequency peak in FIG. 26 areindicative of a periodic structure along the y-direction.

FIGS. 27A-27B are a laser intensity image and a topographical map,respectively, of the coil or antenna 800 in a fourth region (e.g.,corresponding to third region 139 depicted in FIG. 3B) of the coil orantenna 800 in a top plan view obtained using the Keyence VK-X200confocal microscope. FIG. 28 is a plot of the height along they-direction. A periodic structure having an average pitch in they-direction of about 139 microns is visible. FIG. 29 is a plot of themagnitude of the magnitude of the Fourier transform of the surfacetopography in the fourth region. FIG. 30 is a plot of the Fouriertransform along the x-direction and FIG. 31 is a plot of the magnitudeof the Fourier transform along the y-direction in the fourth region. Thepair of large peaks proximal to the zero-frequency peak in FIG. 31 areindicative of a periodic structure along the y-direction.

FIG. 32 is a top plan view of a coil 3300 having a rounded rectangularshape. First and second regions 125 and 130 of the coil are shown. Acomparative coil 3300 available from Worth Electronics as part number760308103202 which has the geometry shown in FIG. 32 and which is arepresentative example of a wound copper wire-based coil was analyzed.

FIGS. 33A-33B are a laser intensity image and a topographical map,respectively, of the comparative coil 3300 in a first region 125 of thecoil 3300 in a top plan view obtained using the Keyence VK-X200 confocalmicroscope. FIG. 34 is a topographical map of a portion of the firstregion 125. FIGS. 35A-35B are plots of the height along the x-directionat smaller and larger x-coordinate length scales, respectively, and FIG.36 is a plot of the height along the y-direction in the first region125. A periodic structure having an average pitch in the x-direction ofabout 336 microns is visible. FIG. 37 is a plot of the magnitude of theFourier transform of the surface topography in the first region. FIG. 38is a plot of the magnitude of the Fourier transform along thex-direction and FIG. 39 is a plot of the magnitude of the Fouriertransform along the y-direction in the first region 125.

FIGS. 40A-40B are a laser intensity image and a topographical map,respectively, of the comparative coil 3300 in a second region 130 of thecoil 3300 in a top plan view obtained using the Keyence VK-X200 confocalmicroscope. FIG. 41 is a topographical map of a portion of the secondregion 130. FIG. 42 is a plot of the height along the x-direction andFIGS. 43A-43B are plots of the height along the y-direction at smallerand larger y-coordinate length scales, respectively, in the secondregion 130. A periodic structure having an average pitch in they-direction of about 334 microns is visible. FIG. 44 is a plot of themagnitude of the Fourier transform of the surface topography in thesecond region. FIG. 45 is a plot of the Fourier transform along thex-direction and FIG. 46 is a plot of the Fourier transform along they-direction in the second region 130 obtained using the Keyence VK-X200confocal microscope.

FIGS. 33A-46 show that the topological pattern of the comparative coil3300 had a periodicity in the x-direction in the first region 125 and aperiodicity in the y-direction in the second region 130. In each case,the topological pattern had a periodicity in the radial direction in thefirst and second regions and did not extend in a same direction in thetwo regions.

FIG. 47 is a top plan view of a coil 4700 having a substantiallycircular shape. A comparative coil 4700 available from SamsungElectronics Co. Ltd. (South Korea) which had the shape illustrated inFIG. 47 and which is a representative example of a flexible printedcircuit coil was analyzed.

FIGS. 48A-48B are a laser intensity image and a topographical map,respectively, of the comparative coil 4700 in a first region 125 of thecoil 4700 in a top plan view obtained using the Keyence VK-X200 confocalmicroscope. FIG. 48C is a topographical map of a portion of the firstregion 125. FIGS. 49A-49B are plots of the height along the x-directionat smaller and larger x-coordinate length scales, respectively, and FIG.50 is a plot of the height along the y-direction in the first region125. A periodic structure having an average pitch in the x-direction ofabout 941 microns is visible. FIG. 51 is a plot of the magnitude of theFourier transform of the surface topography in the first region 125.FIG. 52 is a plot of the magnitude of the Fourier transform along thex-direction and FIG. 53 is a plot of the Fourier transform along they-direction in the first region 125.

FIGS. 54A-54B are a laser intensity image and a topographical map,respectively, of the comparative coil 4700 in a second region 130 of thecoil 3300 in a top plan view obtained using the Keyence VK-X200 confocalmicroscope. FIG. 55 is a topographical map of a portion of the secondregion 130. FIG. 56 is a plot of the height along the x-direction andFIGS. 57A-57B are plots of the height along the y-direction at smallerand larger y-coordinate length scales, respectively, in the secondregion 130. A periodic structure having an average pitch in thex-direction of about 929 microns is visible. FIG. 58 is a plot of themagnitude of the Fourier transform of the surface topography in thesecond region 130. FIG. 59 is a plot of the Fourier transform along thex-direction and FIG. 60 is a plot of the Fourier transform along they-direction in the second region 130.

FIGS. 48A-60 show that the topological pattern of the comparative coil4700 had a periodicity in the x-direction in the first region 125 and aperiodicity in the y-direction in the second region 130. In each case,the topological pattern had a periodicity in the radial direction in thefirst and second regions and did not extend in a same direction in thetwo regions.

In some embodiments, a method of making a coil or antenna includesproviding a rod, providing a film (e.g., a multilayer film including atleast one electrically conductive layer, or any of the multilayer filmsdescribed elsewhere herein), winding the film around the rod to form anassembly (e.g., including a plurality of consecutive turns, orsubstantially concentric loops, of the film substantially concentricwith the rod), and cutting substantially laterally through the assemblyto form the coil or antenna. For example, a segment of the assembly maybe cut from the assembly and this segment includes the coil or antennawrapped around a segment of the rod which can optionally be removed. Thecutting step can create any of the regular patterns described elsewhereherein on one or both (e.g., by slicing through the assembly withparallel spaced apart diamond wires) of the opposing sides of the coilor antenna.

The rod may be extended along an axis and have a cross-sectionorthogonal to the axis that has any suitable shape (e.g., circle, oval,or rounded rectangle (e.g., corresponding to the rounded rectangularshape of the interior region of the coil 3300)). The rod may be composedof any suitable material. Suitable materials may include at least one ofrigid polymers, crosslinked polymers, and epoxy. For example, the rodmay include epoxy (e.g., the rod may be an epoxy rod).

FIGS. 61-64 schematically illustrate a method for making a coil orantenna of the present description.

A rod 410 and a film 420, which may be a multilayer film and/or a filmhaving at least one electrically conductive layer, are provided. In someembodiments, the rod 410 includes a slit 438 for receiving an end 434 ofthe film 420. In some embodiments, the end 434 of the film 420 is placedinto the slit 438 as schematically illustrated in FIG. 61 and the film420 is wound around the rod 410 as schematically illustrated in FIG. 62for a plurality of turns to form the assembly 401 schematicallyillustrated in FIG. 63 . The film 420 can be wound around the rod 410 byturning the rod 410, for example. Tension can be provided along an edge436 while turning the rod 410. The film 420 may correspond to any of themultilayer films described herein (e.g., multilayer film 202 or 402 or502), for example. In some embodiments, the film 420 includes aplurality of alternating metal 10 and first adhesive layers 30; and amagnetically conductive second layer 20 disposed on and bonded to theplurality of alternating metal and first adhesive layers 10 and 30, forexample. The film 420 can be wound around the rod 410 in eitherorientation. For example, in embodiments where the film 420 includes amagnetically conductive or soft magnetic layer 20 closer to oneoutermost major surface of the film 420 than to the other outermostmajor surface, the film 420 can be wound with the layer 20 facingtowards or facing away from the rod 410.

In some embodiments, the film 420 is a multilayer film. In someembodiments, the assembly 401 includes a rod 410, and a multilayer film420 wound around a plurality of consecutive turns substantiallyconcentric with the rod 410. In some embodiments, a length L3 of the rod410 is greater than a lateral width W3 of the multilayer film 420. Insome embodiments, the rod 410 extends beyond at least one lateral edge421 of the multilayer film 420.

In some embodiments, the method further includes cutting the assembly401 into sections having a desired width for a coil. FIG. 64schematically illustrates cutting substantially laterally (e.g., in aplane 6496 having a normal making an angle with an axis of the rod ofless than 45 degrees, or less than 30 degrees, or less than 20 degrees,or less than 10 degrees, or less than 5 degrees) through the assembly toform a separated portion of the assembly which includes a coil orantenna including a plurality of substantially concentric loops of aseparated portion the multilayer film 420. In some embodiments, theseparated portion has a substantially uniform width (e.g., variations inthe width less than 20%, or less than 10%, or less than 5% of an averagewidth). In some embodiments, the separated portion of the assembly has asubstantially uniform width substantially equal (e.g., with 20%, or with10%, or with 5%) to the widths of layers (e.g., first 10, second 20 andthird 30 layers) of the film 420.

In some embodiments, a method of making a coil includes providing a rod410; providing a multilayer film 420; winding the multilayer film aroundthe rod to form an assembly 401 including the rod and a plurality ofloops of the multilayer film substantially concentric with the rod;cutting substantially laterally through the assembly to form a separatedportion 6400 of the assembly where the separated portion of the assemblyincludes the coil and the coil is or includes a plurality ofsubstantially concentric loops of a separated portion the multilayerfilm. In some embodiments, winding the multilayer film around the rod410 includes rotating the rod about an axis of the rod. In someembodiments, the separated portion of the assembly has opposite majorsurfaces and a substantially uniform (e.g., varying by less than 20%, orless than 10%, or less than 5%) width therebetween (e.g., the width W orW1 depicted in FIG. 1B). In some embodiments, the cutting step includescutting or slicing substantially laterally through the assembly using adiamond wire saw. In some embodiments, cutting substantially laterallythrough the assembly includes using a plurality of spaced apart cuttingwires to form a plurality of separated portions of the assembly whereeach separated portion of the assembly includes a coil in the pluralityof coils and each coil includes a plurality of substantially concentricloops of a separated portion the multilayer film.

In some embodiments, the film 420 is a multilayer film corresponding toany multilayer film described elsewhere herein. For example, in someembodiments, the multilayer film 420 includes an electrically conductivefirst layer 10 and a magnetically conductive second layer 20 disposed onthe first layer. In some embodiments, the first layer 10 is magneticallyinsulative. In some embodiments, the multilayer film further includes atleast one electrically conductive third layer 17 disposed on the firstlayer 10. In some embodiments, the at least one third layer 17 ismagnetically insulative. In some embodiments, a relative permeability ofthe second layer 20 is at least 10 times, or at least 100 times arelative permeability of the first layer 10.

In some embodiments, the multilayer film 420 includes a plurality ofalternating electrically conductive 10 and first adhesive 30 layers andincludes a second adhesive layer 41 including an outermost major surface44 of the multilayer film. In some embodiments, the second adhesivelayer 41 is thicker (e.g., at least by a factor of 2 or 4) than thefirst adhesive layer 30. In some embodiments, the second adhesive layer41 includes a composite portion 20 and opposing first and secondadhesive portions 40 and 42 disposed on opposite major surfaces of thecomposite portion 20. In some embodiments, the composite portionincludes a magnetically conductive filler 43 dispersed in a binder.

In some embodiments, the film 420 is or includes an electricallyconductive first layer 10. In some embodiments, the film 420 is amultilayer film including an electrically conductive first layer 10 anda second layer (e.g., 20 or 30 or 40 or 41 or 42) disposed on and bondedto the first layer.

In some embodiments, prior to winding the multilayer film, themultilayer film includes an uncured partially cured first adhesive layer(e.g., 30 or 40 or 41 or 42) bonding the second layer to the firstlayer. In some embodiments, prior to winding the multilayer film, themultilayer film includes an uncured or partially cured second adhesivelayer (e.g., 41 or 42) that includes an outermost major surface 44 ofthe multilayer film. In some embodiments, the step of winding themultilayer film includes bonding adjacent loops in the plurality ofloops through the second adhesive layer. In some embodiments, the methodincludes fully curing the first and second adhesive layers. For example,the first and second adhesive layers may be thermoset adhesive layers(e.g., thermoset epoxy) which can be thermally cured. In someembodiments, the fully curing step is carried out after the winding stepand before the cutting step. In some embodiments, the fully curing stepis carried out after the winding and cutting steps.

In some embodiments, the cutting or slicing step creates an edge surface111 of each loop 110 of the separated portion of the multilayer filmwhere the edge surface includes a regular pattern 120. In someembodiments, the cutting step creates opposing edge surfaces of eachloop of the separated portion of the multilayer film where each of theopposing edge surface includes a regular pattern (e.g., 120 and 120 b,respectively). In some embodiments, a method of making a coil includesproviding an assembly 401 including a rod 410 and a film 420 woundaround a plurality of consecutive turns substantially concentric withthe rod 410 where the film includes an electrically conductive firstlayer 10; and slicing substantially laterally through the assembly usingat least one cutting wire to form a separated portion of the assemblywhere the separated portion of the assembly includes the coil, the coilincludes a plurality of substantially concentric loops of a separatedportion the film 420, and the slicing step creates a first edge surface111 of each loop 110 of the separated portion of the film including afirst regular pattern 120. In some embodiments, the first regularpattern 120 extends substantially along a same first direction andacross substantially the entire coil. In some embodiments, the slicingstep creates opposing first and second edge surfaces 111 and 111 b ofeach loop of the separated portion of the film including respectivefirst and second regular patterns 120 and 120 b. In some embodiments,each of the first and second regular patterns 120 and 120 b extendsubstantially along a same first direction and across substantially theentire coil.

The regular pattern 120 and/or 120 b can be any regular patterndescribed elsewhere herein for the coils or antennas of the presentdescription. For example: In some embodiments, the regular patternextends substantially along a same first direction and acrosssubstantially the entire coil. In some embodiments, the regular patternextends along a first direction making an angle θ with a longitudinaldirection of the loop where θ varies along the longitudinal direction ofthe loop. In some embodiments, the regular patterns of the edge surfacesof at least a plurality of adjacent loops of the separated portion ofthe multilayer film are substantially aligned with each other. In someembodiments, the regular pattern includes a pattern of substantiallyparallel grooves extending across at least a plurality of adjacent loopsof the separated portion of the multilayer film. In some embodiments,the regular pattern has a first average pitch in a first region of thecoil and a different second average pitch in a different second regionof the coil. In some embodiments, a Fourier transform of the regularpattern has a peak at a first spatial frequency in a first region of thecoil and a peak at a different second spatial frequency in a differentsecond region of the coil. In some embodiments, in at least one firstregion of the coil, the coil includes a regular optical andtopographical pattern along a first direction, and a regular optical,but not topographical, pattern along an orthogonal second direction.

In some embodiments, a method includes the step of providing theassembly 401. In some embodiments, the step of providing the assembly401 includes providing the rod 410, providing the film 420, and windingthe film 420 around the rod 410 to form the assembly 401. The method canfurther include inserting the end 434 of the film 420 into the slit 438prior to winding the film 420, and/or can further include heating theassembly to cure any uncured or partially cured adhesive layers.

In some embodiments, a wire saw 6494 is used to cut or slice through theassembly 401. In some embodiments, the wire saw 6494 includes aplurality of spaced apart cutting wires 6495 to form a plurality ofseparated portions (6400 a and 6400 b) of the assembly 401. In someembodiments, each separated portion includes a coil in the plurality ofcoils, and each coil includes a plurality of substantially concentricloops of a separated portion the film 420 (e.g., a multilayer film). Insome embodiments, each separated portion of the assembly has asubstantially uniform width. In some embodiments, the film 420 of theassembly 401 includes an electrically conductive first layer 10. In someembodiments, each separated portion of the assembly includes a pluralityof substantially concentric loops of a corresponding separated portionthe film.

In some embodiments, the cutting wire(s) used to slice through theassembly is/are diamond wire(s). Diamond cutting wires can include awire impregnated with diamond dust and have been used for slicingceramics, for example. FIG. 65 is a schematic illustration of a diamondwire 6595 including diamond particles 6597. Suitable diamond wire sawsare available from Crystal Systems Innovations (Salem, Mas.), forexample.

The coils or antennas of the present description can be used for thetransfer of information (e.g., digital or analogue data) or energy(e.g., for wireless recharging). FIG. 66 is a schematic side view of atransceiver 303 including a coil or antenna 6100 and a first powersource 6310 to energize the coil or antenna 6100. The coil or antenna6100 can be any coil or any antenna of the present description.

If the use of “about” as applied to quantities expressing feature sizes,amounts, and physical properties is not otherwise clear to one ofordinary skill in the art in the context in which it is used anddescribed in the present description, “about” can be understood to meanwithin 10 percent of the specified quantity, but also includes exactlythe specified quantity. For example, if it is not otherwise clear to oneof ordinary skill in the art in the context in which it is used anddescribed in the present description, a quantity having a value of about1, means that the quantity has a value between 0.9 and 1.1, but alsoincludes a value of exactly 1.

All references, patents, and patent applications referenced in theforegoing are hereby incorporated herein by reference in their entiretyin a consistent manner. In the event of inconsistencies orcontradictions between portions of the incorporated references and thisapplication, the information in the preceding description shall control.

Descriptions for elements in figures should be understood to applyequally to corresponding elements in other figures, unless indicatedotherwise. Although specific embodiments have been illustrated anddescribed herein, it will be appreciated by those of ordinary skill inthe art that a variety of alternate and/or equivalent implementationscan be substituted for the specific embodiments shown and describedwithout departing from the scope of the present disclosure. Thisapplication is intended to cover any adaptations or variations of thespecific embodiments discussed herein. Therefore, it is intended thatthis disclosure be limited only by the claims and the equivalentsthereof.

What is claimed is:
 1. An antenna for transfer of information or energy,comprising: an electrically conductive magnetically insulative firstlayer having a width W, a thickness T, and extending longitudinallyalong a length L of the first layer between first and secondlongitudinal ends of the first layer; and a magnetically conductivesecond layer bonded to the first layer along the length of the firstlayer, the first and second layers wound to form a coil comprising aplurality of substantially concentric loops, a width and a length of thesecond layer substantially co-extensive with the respective width andlength of the first layer so as to expose opposing longitudinal edgesurfaces of the first layer along the length of the first layer; whereinat least one of the opposing longitudinal edge surfaces of the firstlayer and the second layer comprises a regular pattern extendingsubstantially laterally across the edge surface, the regular patterns ofthe edge surfaces of at least a plurality of adjacent loops in theplurality of substantially concentric loops being substantially alignedwith each other across substantially the entire coil.
 2. The coil ofclaim 1, wherein the regular pattern has a first average pitch in afirst region of the plurality of substantially concentric loops and adifferent second average pitch in a different second region of theplurality of substantially concentric loops.
 3. The antenna of claim 1,wherein a Fourier transform of the regular pattern has a peak at a firstspatial frequency in a first region of the plurality of substantiallyconcentric loops and a peak at a different second spatial frequency in adifferent second region of the plurality of substantially concentricloops.
 4. The antenna of claim 1, wherein the electrically conductivemagnetically insulative first layer has a relative permeability of lessthan 1.4 and the magnetically conductive second layer has a relativepermeability of greater than
 10. 5. A substantially planar coil fortransfer of information or energy, comprising: an electricallyconductive magnetically insulative first layer; and a magneticallyconductive second layer disposed on and bonded to the first layer andsubstantially co-extensive in length and width of the first layer so asto not cover edge surfaces of the first layer; wherein the first andsecond layers are wound to form a plurality of substantially concentricloops and wherein in a plan view, the coil comprises a regular patternextending substantially along a same first direction and acrosssubstantially the entire coil including the first layer and the secondlayer.
 6. The coil of claim 5, wherein the regular pattern has a firstaverage pitch in a first region of the coil and a different secondaverage pitch in a different second region of the coil.
 7. The coil ofclaim 5, wherein a Fourier transform of the regular pattern has a peakat a first spatial frequency in a first region of the coil and a peak ata different second spatial frequency in a different second region of thecoil.